Flip-Chip LED Electrode Rings Prevent Short-Circuiting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Flip-chip light-emitting diodes face issues with short-circuiting due to damage of the insulating layer during chip backend processes, leading to poor packaging yield and increased manufacturing costs, particularly for large size designs, as well as uneven solder paste distribution and electric leakage.
Innovation Solution
Incorporating electrode rings with greater thickness than the electrode bodies as barrier structures to prevent short-circuiting during packaging and usage, and simplifying the fabrication process by eliminating the need for dry or wet etching to form a side-wall insulating layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional insulating layer is used to prevent short-circuiting, then electrical isolation is achieved, but the insulating layer is damaged during backend processes (grinding, cutting, sawing) or caused by stress, leading to short-circuits and poor packaging yield
Solution Approach 1:
The patent removes the traditional insulating layer from the chip structure and replaces it with electrode rings that perform both electrical connection and physical barrier functions. This extraction of the insulating layer eliminates the problem of its damage during backend processes while maintaining electrical isolation through the electrode ring design.
Solution Approach 2:
The electrode rings serve multiple functions: they provide electrical connection (conductive function) and simultaneously act as a physical barrier preventing solder paste overflow (barrier function). This multi-functionality replaces the traditional separate insulating layer, eliminating the reliability issue of insulating layer damage while maintaining both electrical isolation and mechanical robustness.
2Reliability
If dry or wet etching processes are added to form side-wall insulating layer, then insulating performance is improved, but manufacturing complexity and costs increase significantly
Solution Approach 1:
The patent extracts and eliminates the complex etching processes (dry or wet etching) from the fabrication workflow. Instead of adding side-wall insulating layers through multi-step etching, the design uses the electrode rings themselves as the barrier structure, which can be formed through simpler deposition and patterning processes, thereby reducing manufacturing complexity.
Solution Approach 2:
Instead of adding insulating material to prevent short-circuits (traditional approach), the patent inverts the approach by using conductive electrode rings with increased thickness to serve as the barrier. This inversion eliminates the need for complex etching processes while achieving the same protective function through a simpler fabrication route.
3Ease of operation
If solder paste welding is adopted in packaging, then electrical connection is achieved, but solder paste is distributed unevenly or overflows welding plate area, causing short-circuits and reduced packaging yield
Solution Approach 1:
The patent applies preliminary anti-action by designing electrode rings with increased thickness before the soldering process. These thicker electrode rings create a physical barrier that prevents solder paste from overflowing the welding plate area during the welding process, thereby preventing short-circuits before they can occur and improving packaging yield.
4Use of energy by moving object
If large size chip design is used to improve light-emitting efficiency and current distribution, then optical performance is improved, but the positions of P and N metal electrodes are limited and insulating layer at grain edge is more prone to damage
Solution Approach 1:
The patent extracts the vulnerable insulating layer from the large-size chip design and replaces it with electrode rings that extend to the chip edges. This elimination of the insulating layer removes the weak point at the grain edges that is prone to damage during backend processes, while the electrode rings provide both electrical connection and edge protection for large-area chips.
Data Source
AI summary
A flip-chip light-emitting diode structure includes a substrate; an epitaxial layer over the substrate, which includes a first semiconductor layer, a light-emitting layer, and a second semiconductor layer; a first electrode structure over the first semiconductor layer; a second electrode structure over the second semiconductor layer; wherein, the first electrode structure includes a first electrode body and a first electrode ring; the second electrode structure includes a second electrode body and a second electrode ring; the thickness of the first electrode ring is greater than or equal to that of the first electrode body and the thickness of the second electrode ring is greater than or equal to that of the second electrode body. As barrier structures, the first and the second electrode rings are used for avoiding short circuit during packaging and usage of the light-emitting diode due to overflow of solid crystal conductive materials, thus improving reliability.